Tierd,
Just because we're not talking on the r/t doesn't mean we're not working.
As ATCO 2 says, runway management is all about priorities: We can be on the phone coordinating with radar, talking to GMC, looking for a Virgin with a tight slot,
trying to get Flow to release someone early....and on and on. So that frantic burst of activity gives us the opportunity to get on with other tasks in the knowledge that the runway/departure order is sorted for the next 5/10 mins.